down counter using 74193 ic

Discussion in 'Digital Circuit Design' started by Judy Ann, Oct 1, 2016.

  1. Judy Ann

    Thread Starter New Member

    Oct 1, 2016
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    guys i need help! please give me an idea or schematic diagram of circ, about down counter using 74193 ic ..
     
  2. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    • Down from what?
    • To what?
    • Do you know how it starts?
    • Will it run once or how will it reset?
    • When will it stop?
     
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  3. Judy Ann

    Thread Starter New Member

    Oct 1, 2016
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    DOWN FROM 0 TO 9 .. IT WILL RESET AT 0 THEN BACK TO 9...
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    Can you count from 9 to 0 backwards?
     
  5. Judy Ann

    Thread Starter New Member

    Oct 1, 2016
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  6. djsfantasi

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    Apr 11, 2010
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    Is this homework? And there were a couple of my questions you did not answer.

    Have you read the datasheet?
     
  7. Judy Ann

    Thread Starter New Member

    Oct 1, 2016
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    this is an activity, yes i have read the data sheet.. i have tried my idea but the count is 9-7-5-3-1, then back to 9..

    circuit must have a continuity sir, it will not run once...
     
  8. Alec_t

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    Sep 17, 2013
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    Post the circuit of your idea.
    Is the 'activity' a school/college project?
     
  9. djsfantasi

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    Apr 11, 2010
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    And how does it start? Just by powering on?

    Is the count from 9 to 0 or is it 9-7-5-3-1? Details are important?

    Assuming it's the latter sequence, is there something unique about it? Can you describe it to us? How would you represent it in binary?
     
  10. Judy Ann

    Thread Starter New Member

    Oct 1, 2016
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    IMG_20161002_211953.jpg
    this is the schematic.. i need it for college project
     
  11. Judy Ann

    Thread Starter New Member

    Oct 1, 2016
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    by putting the source on.. the count is from 9-7-5-3-1.. there is nothing unique .. when i turn on the source the clock pulse start then the 7segment just display 9-7-5-3-1 number again and again... 1001 - 0111 - 0101 - 0011 - 0001..
     
  12. Alec_t

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    Sep 17, 2013
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    Using the A,B,C,D inputs, what value do you need to load in to reset the counter?
     
  13. Judy Ann

    Thread Starter New Member

    Oct 1, 2016
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    need the 1 NAND 1 value to reset the counter. 0101,0111,1101,1111???
     
  14. djsfantasi

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    Apr 11, 2010
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    Alec_T asked a good question!

    And may I add, there IS something unique about that sequence. Look at it again, either in decimal or binary...
     
  15. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Have a good look at the binairy values of the A,B,C and D outputs.
    How do they relate to the wanted sequence?
    Also what values do you need at the input of the counter to start at 9?

    Bertus
     
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  16. Judy Ann

    Thread Starter New Member

    Oct 1, 2016
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    need 1001 value to start at 9.
     
  17. Judy Ann

    Thread Starter New Member

    Oct 1, 2016
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    there is nothing unique , the circuit just display 9-7-5-3-1 values
     
  18. Papabravo

    Expert

    Feb 24, 2006
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    I'm going to be a spoil sport and let you off the hook. In the given sequence the least significant digit is always a 1. So tie that input to the display high. What do the remaining digits do? That's right they go {100, 011, 010, 001, 000}. Those values concatenated with a constant, always 1, least significant digit, make up the desired sequence. Preset the counter to 4, aka 100, let it count down to 0, and reset the counter to 4 on the next clock after the counter reaches 0. Recognizing patterns is half the secret to clever logic and state machine design. It has always worked for me.
     
  19. Alec_t

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    Sep 17, 2013
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    I'm still puzzled. Do you want to count 9-8-7-6-5-4-3-2-1-0-9-8-7-6-........; or should it be 9-7-5-3-1-0-9-7-5-....... ?
     
  20. MrChips

    Moderator

    Oct 2, 2009
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    Seems like the LSB is stuck high.
     
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